Conservative watchdog group Judicial Watch on Thursday sought to intervene in a court case that could determine if Maryland voters face a question about illegal immigrants on next year’s presidential ballot.

Opponents of the new Maryland law, which would give undocumented immigrants breaks on in-state college tuition rates, gathered enough signatures in July to force the issue to a statewide referendum.

But last month an immigrant rights group filed a lawsuit seeking to block the referendum and to keep the issue off the 2012 ballot.

Casa of Maryland alleged that the law, dubbed the Maryland Dream Act, was off-limits to a referendum because it dealt with a state spending issue. It also demanded that tens of thousands of signatures that Republicans had gathered online should be thrown out.

Following a conference on Thursday in Anne Arundel County Circuit Court, Judicial Watch announced it had filed a Motion to Intervene on behalf of, the online site set up by Republican state lawmaker Del. Neil Parrott of Washington County.

“Casa [of] Maryland and the illegal alien lobby are attempting to throw out over 100,000 validated voter signatures and ignore the will of the people,” Parrott said in a statement distributed by Judicial Watch. “Those who oppose the referendum process are doing so because they know how unpopular this bill is and, fearing that they will lose at the ballot box, have mounted this lawsuit to prevent Marylanders from exercising their constitutional right to decide the issue on their own.”

Casa declined to comment. Hearings on the merits of the case will likely begin in January.

Judicial Watch has a long history on the issue. Recently, a Montgomery County Circuit Court judge dismissed a lawsuit by the group that had challenged Montgomery College for its practice of charging lower resident tuition rates to illegal immigrants who graduate from local high schools.

Maryland’s law bucks a trend of states moving to deny in-state tuition discounts for illegal immigrants, but Gov. Martin O’Malley (D), who signed the law in May, has used it to draw attention to a controversial part of Republican Gov. Rick Perry’s record.

Early in his tenure, Perry supported a law giving in-state tuition rates to illegal immigrants and has stood by the move recently in moments of heated debate with other GOP presidential hopefuls.

“I do admire [Perry’s] willingness to stand up to the immigrant-bashers and the thinly veiled racism and scapegoating that’s so rampant in their party and directed at new Americans,” O’Malley said last week.

Del. Patrick L. McDonough, a Baltimore County Republican who was heavily involved in the petition drive and who is considering a run for Congress, derided those comments as hate speech against “decent people” who oppose illegal immigration.

If the referendum effort succeeds in court, it would be the first time in 20 years that a petition drive has forced a vote on a Maryland law.

Under the law, undocumented immigrants who can prove that they have attended Maryland high schools for at least three years and that their parents or guardians have begun filing taxes were to have been allowed to begin courses this fall at community colleges at in-state rates.

Students who obtain an associate’s degree would be allowed to seek in-state rates to continue pursuing a bachelor’s degree. For a four-year degree, the plan could cost Maryland substantially per student. State analysts had estimated that hundreds of undocumented high-school graduates would begin applying for aid this summer.

Immigrant groups say the referendum effort tossed those students’ college plans into limbo, and for some, left college this fall out of reach financially.